Particle beam system with multi-source system and multi-beam particle microscope

Abstract

This invention discloses a particle beam system with a multi-source system. The multi-source system includes an array of electron emitters, which serves as a multi-source particle system. In this multi-source system, the heterogeneous emission characteristics of the various emitters are corrected or pre-corrected for subsequent particle optical imaging using particle optics components (which can be manufactured using MEMS technology). The beam current of the individual particle beams can be adjusted within this multi-source system.

Description

Technical Field

[0001] This invention relates to a particle beam system employing multiple particle beam operations. Prior Technology

[0002] Like single-beam particle microscopy, multi-beam particle microscopy can be used to analyze objects at the microscopic scale. For example, an image of an object (representing the surface of that object) can be recorded using these particle microscopes. Thus, for example, the structure of that surface can be analyzed. While in single-beam particle microscopy, a single beam of charged particles (such as electrons, positrons, muons, or ions) is used to analyze the object, in multi-beam particle microscopy, multiple beams of particles are used for this purpose. These multiple beams (also called bundles) are simultaneously directed at the surface of the object, thus allowing a significantly larger area of ​​the object's surface to be sampled and analyzed compared to single-beam particle microscopy over the same period.

[0003] WO 2005 / 024 881 A2 discloses a multi-particle beam system in the form of an electron microscope system, employing multiple electron beam operations to scan an object to be examined using a parallel electron beam. This electron beam is generated by an electron source directed at a porous plate with multiple openings. One portion of the electrons in the beam strikes and is absorbed by the porous plate, while another portion passes through the openings in the porous plate, thus shaping the electron beam in the beam path downstream of each opening, the cross-section of which is defined by the cross-section of the opening. Furthermore, the appropriately selected electric field provided in the beam path upstream and / or downstream of the porous plate has the effect that each opening in the porous plate acts as a lens on the electron beam passing through that opening, so that the electron beam is focused in a plane at a distance from the porous plate. The plane (where the focal points forming the electron beams) is imaged onto the surface of the object to be examined by a downstream optical unit, such that the individual electron beams strike the object in a focused manner as main beams. There, interaction products (such as backscattered electrons or secondary electrons) emitted from the object are generated, which are shaped to form secondary beams and guided at a detector by a further optical unit. Each of these secondary beams strikes a separate detector element, such that the electron intensity detected by the detector element provides information about the object at the location where the corresponding main beam struck the object. The main beam systematically scans the surface of the object to produce an electron micrograph of the object in a manner commonly used in scanning electron microscopy.

[0004] In the described multiple particle beam systems, high resolution and high throughput are highly relevant to satisfactory and successful practical use. In this context, it is particularly necessary to set the intensity of these particle beams.

[0005] US 2017 / 0025241 A1 discloses a multi-beam particle beam system in which the current density within the particle beams is variable. Specifically, the irradiance is set before the multi-beams are even formed from the main electron beam. To set the irradiance, a dual collimator is used, as described in US 2017 / 0025241 A1, which is directly downstream of the electron source in the beam direction. By varying the excitation of the lens of the dual collimator, the current density of the electrons passing through the openings in the porous plate downstream of the dual collimator can be varied.

[0006] However, if the number of particle beams used is further increased, the multi-beam particle beam system described above reaches its limit. Even to obtain sufficient beam current for each individual beam, it is necessary to use as many particles as possible from the particle source. However, in that case, the emission characteristics of the particle source become more important, specifically the uniformity of the emission characteristics across the entire utilized emission angle. When using relatively large emission angles, the emission characteristics of particle sources, such as thermal field emission (TFE) sources, are no longer uniformly distributed. Therefore, in the corresponding particle beam system, the irradiance at the aperture plate is subsequently no longer uniformly distributed, and there are relatively large variations in the current density across different individual beams. However, in the case of a multi-particle detection system, there is a system requirement for only small variations (typically less than a few percent) in the current intensity between these various individual beams, so that all individual image fields of the multi-image field are scanned using an equivalent number of particles or electrons per pixel. For example, this is a prerequisite for obtaining individual images with roughly the same brightness.

[0007] Therefore, the use of particle sources with large emission angles, and the significant current requirements for each individual beam, present a challenge in detection systems operating with multi-beam particle beam systems due to these varying emission characteristics.

[0008] Furthermore, multi-beam particle beam systems using multi-source operation already exist. This approach also increases the number of individual particle beams available for such multi-beam particle beam systems. In principle, photocathodes and cold field emitter arrays (cold FEAs) are known as multi-source systems. However, the disadvantages of using photocathodes are their unstable emission characteristics, short lifespan, and low brightness. In contrast, cold field emitter arrays have relatively high brightness and a smaller virtual source size. Moreover, they can be produced using methods conventional in microstructure technology, such as the combination of lithography and subsequent etching and / or deposition methods (MEMS technology; microelectromechanical systems technology). However, the emission characteristics of cold field emitter arrays remain non-uniform, and it is difficult to produce individual tips for emission with reproducible characteristics and specifications, especially considering their emission characteristics, overall current, and virtual source diameter.

[0009] US 2014 / 0057212 A1 discloses a lithography system employing multiple individual particle beams. It does not contain a multi-source system, but rather a single source.

[0010] US 2016 / 0111251 A1 discloses a multi-beam electron microscope that also uses a single source instead of a multi-source operation. Furthermore, it discloses different options for field curvature correction.

[0011] DE 10 2014 008 083 A1 discloses a single-source particle beam system. Various arrangements of a multi-aperture plate for beam shaping are disclosed, and in particular, a field generator for generating a multipole field is disclosed.

[0012] US 2012 / 0295203 A1 discloses a lithography system employing single-source operation. In the region close to the source, a two-stage system is disclosed, comprising a series of individual lenses for setting the relative positioning of the crossover point.

[0013] US 2014 / 0042334 A1 discloses a single-source lithography system.

[0014] US 8,618,496 B2 discloses various field generators used to manipulate individual particle beams. No multi-source systems are disclosed.

[0015] WO 2007 / 028595 A2 discloses a single-source particle beam system. Various porous plate arrangements are disclosed, wherein the beam is also made of plates with curved surfaces and therefore varying distances between them.

[0016] US 2013 / 0344700 A1 discloses a further lithography system employing single-source operation.

[0017] US 8,384,051 B2 discloses a further lithography system employing single-source operation. The cited literature focuses on issues related to detection.

[0018] WO 2005 / 024881 A2 discloses a multi-particle beam system employing single-source operation. Various configurations of the multi-aperture plate are disclosed, and several states of image field effect correction are discussed. Summary of the Invention

[0019] Therefore, the object of the present invention is to provide a particle beam system employing multiple individual beam operations, which ensures good beam uniformity of these individual beams, even when using a large number of individual beams and (simultaneously) high beam currents for each individual beam. In particular, this particle beam system should also be applicable to multi-beam detection systems.

[0020] A further objective of this invention is to increase the throughput of the particle beam system.

[0021] One further object of the present invention is to improve the availability of multiple sources for multi-beam particle beam systems.

[0022] A further objective of this invention is to minimize imaging aberrations in the particle beam system.

[0023] This objective is achieved by the independent patent claim. Preferred embodiments of the invention are apparent from the supplementary patent claims.

[0024] This patent application claims priority to German patent application No. 10 2020 115 183.7, the entire disclosure of which is incorporated herein by reference.

[0025] Here, the present invention is based on the following considerations: if the inhomogeneities in the beam current density of the individual particle beams from the multi-source are compensated for or removed before the actual particle optical imaging occurs, existing multi-source particle sources (which generate electrons via cold field emission for high-resolution and high-throughput particle beam systems) can be used. According to the invention, it is therefore proposed to initially coarsely shape the individual particle beams close to the multi-source, wherein MEMS technology can be used to manufacture the lenses, deflectors, stigmators, etc., used in this process. The actual final beam shaping (whereby the individual particle beams are formed for high-resolution particle optical imaging) is performed only later within the particle beam system. Near the multi-source, the energy of the individual particle beams remains relatively low, and the individual particle beams can be influenced or deflected using relatively low voltages or currents. Furthermore, low voltages or currents are a good prerequisite for low-risk design of MEMS devices, with a relatively high requirement being the insulation of the wiring traces on them.

[0026] Moreover, due to this two-stage shaping of the individual particle beams, it is possible to pre-fine the individual particle beams originally emitted by the multi-source source close to its source; this reduces the Coulomb effect, which is a disadvantage considering high resolution.

[0027] Specifically, according to a first-state sample, the present invention relates to a particle beam system comprising the following: A multi-source system includes - A single particle source, particularly an electron emitter array, configured to generate multiple beams of individually charged particles via field emission, particularly cold field emission; - A first porous plate having multiple first openings through which the individual particle beams pass at least partially; - A first multi-lens array comprising multiple individually adjustable particle lenses, and disposed in the beam path downstream of the first multi-aperture plate, such that the individual particle beams passing through the first multi-aperture plate also pass through the first multi-lens array; - A second aperture plate having multiple second openings is disposed downstream of the first multi-lens array in the beam path, such that the individual particle beams passing through the first multi-lens array also pass through the second aperture plate; and - A beam current-limiting porous plate having multiple beam current-limiting openings disposed downstream of the second porous plate in the beam path, such that individual particle beams are partially incident on and absorbed by the beam current-limiting porous plate, and partially pass through the openings in the beam current-limiting porous plate; and - A controller configured to supply an adjustable excitation to the particle lenses of the first multi-lens array, and thus individually set the focus of the associated particle lens for each individual particle beam.

[0028] Therefore, in this case, the multi-source system generates electrons or emits electron beams. The multi-source particle system can be specifically implemented as an electron emitter array, wherein the individual emitters or tips are arranged in a regular pattern. For example, it can be arranged in a checkerboard pattern or a hexagonal pattern. For example, this electron emitter array can be fabricated using MEMS technology, where methods such as lithography are combined with subsequent etching and / or deposition methods. For example, metal emitters, silicon-based emitters, and / or carbon nanotube-based emitters are suitable for the emitters in such electron emitter arrays. The multi-source particle system comprises multiple real particle sources; in particular, it can have multiple tips.

[0029] In this multi-source system, the first porous plate, the first multi-lens array, and the second porous plate are arranged in sequence in the beam path downstream of the multi-source particle system. Here, for the purposes of this patent application, a comparison is made between the porous plate of one aspect and the multi-lens array of the other. The porous plate is a plate material with multiple openings. Voltage can be applied to the entire porous plate. This is possible, but not necessary. In any case, all openings in the porous plate have a uniform, globally identical potential. In contrast, the multi-lens array of this patent application is a more complex component than the porous plate: The multi-lens array comprises multiple lenses, substantially arranged parallel to each other, each individually adjustable and independent, such that these individual lenses of the multi-lens array can have different refractive powers, and these refractive powers can vary independently for each lens on an individual basis.

[0030] According to a preferred embodiment variant, a multi-lens array includes the following: - A multi-aperture plate with multiple openings; and - Multiple electrodes, which are arranged around the multiple openings in the multi-aperture plate of the lens, to individually affect the individual particle beams passing through the respective openings.

[0031] For example, these electrodes can be ring electrodes; however, other specific embodiment variations are also possible. For example, in the case of electrodes divided at the azimuth angle (such as quad or octagonal electrodes), the same voltage may be applied to all electrodes. Furthermore, the focusing effect can be induced by a coil (which encloses each opening in the lens aperture plate in a plane perpendicular to the beam direction). For deflection coils, this is described in DE 10 2014 008 083 B4.

[0032] Preferably, the openings in the first porous plate, the second porous plate, and the first multi-lens array are circular in each case, and overall, the individual openings are arranged in a hexagonal structure; however, other arrangement options are also possible. The number of openings in the first porous plate, the second porous plate, and the first multi-lens array can be matched with the number of individual particle beams or with the number of emitters or tips of the multi-source particle system. In this case, in the hexagonal arrangement, it is preferable if the number of individual particle beams formed is ,in Let m be any natural number. However, alternatively, a plurality of individual particle beams may be formed from a single emitter. For example, this can be achieved by the first porous plate having more openings, specifically m openings per emitter. However, in that case, it is further preferred that the number of openings in the first porous plate, the second porous plate, and the first multilens array are the same in each case. Moreover, these openings should be concentrated above each other in the beam path of the individual particle beams. Here, it is preferable that the diameter of the openings in the first porous plate is smaller than the diameter of the openings in the first multilens array and the second porous plate. Unlike the case of the first multilens array and the second porous plate, the individual particle beams at least partially pass through the first porous plate; that is, the first porous plate can also block electrons emitted by the emitters.

[0033] The first aperture plate, the first multi-lens array, and the second aperture plate each contain a series of openings that form individual lenses. In this case, a substantially identical first voltage U1, which may also be zero, is applied to both the first and second aperture plates. In contrast, the individual adjustable voltages U2 + Vi at the first multi-lens array are substantially different from the first voltage U1. In this case, the notation Vi indicates that the adjustable voltages vary around the value U2, i.e., U2 is an average or reference value.

[0034] Depending on the excitation of these individual adjustable particle lenses, the order of the openings in the first multi-aperture plate, the first multi-lens array, and the second multi-aperture plate has different focusing effects. Therefore, after passing through these individual lenses, the individual particle beams have different divergences and subsequently expand to different ranges along a short path of deviation. These subsequently expanded individual particle beams are incident on the beam current-limiting multi-aperture plate with multiple beam current-limiting openings. Some particles of these individual particle beams collide with and are absorbed by the beam current-limiting multi-aperture plate, while others pass through the openings in the beam current-limiting multi-aperture plate. This allows the beam current intensity to be individually set for each individual particle beam within the multi-source system. Therefore, in particular, the different emission characteristics or current intensities of these individual sources or tips can be compensated for by adjusting the program. Thus, conventional multi-source particle systems based on electron emitter arrays can also be used in high-resolution particle beam systems. The final beam shaping of the individual particle beams used for the actual particle optical imaging is performed only later in the particle beam system. Preferably, immediately after passing through the beam current limiting aperture plate, the following relationship applies to the deviation δ of the individual beam currents from the arithmetic mean of the beam currents: δ ≤ 5%, preferably δ ≤ 2%, and most preferably δ ≤ 1%.

[0035] The controller configured to supply individually adjustable excitation to the particle lenses of the first multi-lens array, and thus individually adjust the focusing of the associated particle lens for each individual particle beam, can be the same controller used for the entire particle beam system. However, this is not necessary. In particular, the adjustable excitation system voltage and / or current.

[0036] Furthermore, the openings in the beam current limiting aperture plate are preferably aligned with respect to the openings in the first aperture plate, the first multi-lens array, and the second aperture plate. The diameter of the beam current limiting openings is smaller than the diameter of the openings in the second aperture plate and the first multi-lens array.

[0037] The second aperture plate and the beam current limiting aperture plate can also be functionally combined or integrated with each other. Therefore, the second aperture plate and the beam current limiting aperture plate do not necessarily have to be two separate components. However, structural separation has electro-optical advantages.

[0038] According to a preferred embodiment of the present invention, the particle beam system further includes a final beam-shaping system disposed downstream of the multi-source system in the beam path, and by means of the individual particle beams having a shape for subsequent particle optical imaging. In this case, the term "final beam-shaping" indicates that the individual particle beams ultimately used for the actual relevant particle optical imaging are formed by the final beam-shaping system. Within the scope of final beam-shaping, the subsequent particle optical imaging is performed taking into account or setting parameters such as homogeneous individual particle beam current density, rotation, telecentricity, astigmatism (to be removed). Due to these settings, high-resolution and high-throughput particle optical imaging is possible. The individual structural components of the final beam-shaping system will be discussed in more detail below within the scope of this patent application.

[0039] According to a preferred embodiment of the invention, the first perforated plate is specifically implemented as an extraction electrode; and / or the second perforated plate is specifically implemented as a corresponding electrode; and / or the (final) beam current limiting perforated plate is specifically implemented as an anode. This embodiment variant is based on the fact that existing particle multiple sources, which generate multiple individually charged particle beams by field emission in any case, have various electrodes in the form of perforated plates. In this case, the same voltage can be applied to the extraction electrode and the corresponding electrode. The same voltage, or a different voltage, can also be applied to the anode.

[0040] According to a preferred embodiment of the present invention, the following relationship applies to the distance A between the particle multi-source and the beam current limiting aperture plate: 0.1 mm ≤ A ≤ 30 mm, preferably 0.1 mm ≤ A ≤ 20 mm, and most preferably 0.1 mm ≤ A ≤ 10 mm. Therefore, the beam current limiting aperture plate is very close to the particle multi-source. In this case, the distance A is measured from the tip of the particle emitter to the surface of the beam current limiting aperture plate facing the particle multi-source. Therefore, the thickness of the multi-source system in the direction of the optical axis Z of the particle beam system is less than 30 mm, preferably less than 20 mm, and most preferably less than 10 mm. In this case, the multi-source system may still have further components that contribute to the overall thickness or overall range of the multi-source system.

[0041] According to a further embodiment of the invention, the multi-source system further includes a suppression electrode. A voltage is applied to this electrode such that it forces electrons out of the source region of the multi-source particle system.

[0042] According to a further embodiment of the invention, the multi-source system includes a second multi-lens array comprising multiple individually adjustable and focusing particle lenses, disposed downstream of the beam current limiting aperture plate in the beam path, such that particles of the individual particle beams passing through the beam current limiting aperture plate also substantially pass through the second multi-lens array. Furthermore, the controller is configured to supply individually adjustable excitations to the particle lenses of the second multi-lens array, and thus individually set the focusing of the associated particle lens for each individual particle beam. In particular, the first and second multi-lens arrays may have the same design, which simplifies the manufacture of the particle beam system. However, the first and second multi-lens arrays may also have different configurations. Moreover, these statements have been made with respect to the first multi-lens array applicable to the second multi-lens array. Due to the individually adjustable excitations, the second multi-lens array can individually set the focal length for each of the respective individual particle beams. As the particles pass through the first multi-lens array, the focal length of each individual particle beam is slightly altered due to the different excitations by the lenses used for those individual particle beams. These deviations can now be corrected by providing the second multi-lens array. Furthermore, the second multi-lens array allows for field curvature correction for subsequent particle optical imaging. This is because if the subsequent field curvature (caused by the subsequent particle optical imaging) is known, it can be compensated for by the appropriate excitation of the particle lenses in the second multi-lens array.

[0043] According to a further preferred embodiment of the invention, the multi-source system further includes a first multi-deflector array through which the individual particle beams pass and is disposed in the beam path downstream of the beam current-limiting porous plate. Here, the controller is further configured to supply individual adjustable excitations to the first multi-deflector array, thereby individually deflecting the individual particle beams. In this case, for example, the multi-deflector array serves as a direction correction for the individual particle beams. For example, beam migration that may occur due to openings in the porous plate (which may be misaligned due to manufacturing tolerances) can be compensated. This structure of the multi-deflector array is known in principle (see, for example, DE 10 2014 008 083 B9); this is preferably with respect to the electrostatic deflection field in the openings of the multi-deflector array. In this case, electrodes that are subdivided in the azimuth direction and can be driven in pairs for appropriate direction correction can be provided.

[0044] According to a preferred embodiment of the invention, the multi-source system further includes an array of aberration compensators through which the individual particle beams pass. In this case, the controller is further configured to supply adjustable excitation to the array of aberration compensators. The aberration compensators of the array provide a multipolar field, which depends on the excitation of the aforementioned aberration compensators, and can be used to change the position and angle of the individual particle beams incident on the object to be inspected. However, this may also affect the astigmatism of each individual particle beam. The imaging aberrations of the particle optical imaging are correctable.

[0045] According to a preferred embodiment of the present invention, the multi-source system is at least partially manufactured using MEMS technology. Furthermore, it is possible that all components of the multi-source system have been manufactured using MEMS technology.

[0046] According to a preferred embodiment of the present invention, the multi-source particle emitter has at least one of the following emitter types: metal emitter, silicon-based emitter, and carbon nanotube-based emitter.

[0047] According to a further preferred embodiment of the invention, the particle beam system further includes a magnetic field generating member, which is configured such that the multiple particle sources are disposed within a magnetic field. Specifically, in this case, the emitter plane containing the tips of the multiple sources is disposed within the magnetic field. Therefore, the charged particles or electrons initiate within the particle beam system within the magnetic field; thus, they are generated within the magnetic field. The targeted arrangement of the magnetic field relative to the emitter plane makes it possible to imprint a defined initiation angle distribution onto the electrons. Therefore, their initial velocity vectors projected onto the emitter plane have a specific direction, specifically orthogonal to the respective applied magnetic fields. This embodiment variant is preferred because it provides the opportunity to correct the landing angle in the object plane or on the sample. In principle, the aberrations occurring in the object plane are proportional to the focal length of the image side. To obtain a shorter focal length of the object lens (which results in smaller aberrations), the operation can be performed using magnetic immersion. However, this results in the object plane still being located within the magnetic field. Therefore, the individual particle beams incident on the plane of the object or on the object undergo Larmor rotation, which is proportional to the radius R or the distance to the optical axis Z. Consequently, these individual particle beams possess angular momentum about the optical axis Z. This angular momentum can be compensated at the source by providing a suitable magnetic field. This facilitates the telecentric landing of these individual particle beams within the plane of the object. This is particularly desirable when examining so-called high aspect ratio (HAR) structures, where the ratio of width to depth can be approximately 1:100 or greater.

[0048] According to a preferred embodiment of the invention, the magnetic field generated by the magnetic field generating member has a component perpendicular to and / or parallel to the emission direction of the charged particles from the multiple sources. In this case, the perpendicular component ensures that the generalized angular momentum is deflected or imprinted onto the electrons in the magnetic field.

[0049] According to a further preferred embodiment variant, the magnetic field generating component is implemented such that the initial angular distribution of the charged particles, induced by the magnetic field after their emission from the particle source, is determined by the radial distance from the particle source to the optical axis of the particle beam system. This particularly favors the correction of any Larmor rotation occurring in the object plane, which is proportional to the distance r between the incident point and the optical axis Z.

[0050] In this case, the magnetic field generating component may have integral or partial embodiments. For example, it may include a pole piece, with coils arranged in a suitable manner. In this case, it is preferable to position the magnetic field generating component on the side of the particle beam system away from the beam path, such as above the particle multi-source or above the entire multi-source system.

[0051] According to a further preferred embodiment of the present invention, the particle beam system further comprises the following: - A focusing lens system, which is positioned downstream of the multi-source system and upstream of the final beam shaping system in the direction of the beam path; - A field lens system, which is positioned downstream of the final beam shaping system in that direction of the beam path; and - An object lens system, which is positioned downstream of the field lens system in the direction of the beam path. One of the intermediate image planes is formed between the final beam shaping system and the field lens system.

[0052] The final beam shaping system is positioned downstream of the multi-source system in the beam path (as explained above) and is used to shape the individual particle beams for subsequent particle optical imaging. In this case, shaping the individual particle beams by means of the final beam shaping system is performed at relatively high energies of the individual particle beams, and therefore has high accuracy. Furthermore, this accuracy is decisive for the quality of the subsequent particle optical imaging from the intermediate image plane onto the object plane. In this case, the images from the multiple sources are located in the intermediate image plane; therefore, it can be regarded as a virtual particle source for performing the subsequent imaging from the intermediate image plane to the object plane.

[0053] According to a preferred embodiment, the final beam shaping system includes the following: - A final porous plate having multiple openings, configured such that individual particle beams are partially incident on and absorbed by the final porous plate, and partially pass through the openings in the final porous plate; and - A third multi-lens array comprising multiple adjustable particle lenses, positioned downstream of the final multi-aperture plate in the beam path, such that the individual particle beams passing through the final multi-aperture plate also substantially pass through the third multi-lens array. The controller is further configured to supply an adjustable excitation to the particle lenses of the third multi-lens array.

[0054] In this case, all lenses of the third multi-lens array may undergo the same excitation; however, the lenses of the multi-lens array may also be excited differently on an individual basis. Only the components of the individual particle beams suitable or intended for particle optical imaging pass through the final multi-aperture plate. Thus, the individual particle beams are geometrically shaped by the final multi-aperture plate. In contrast, the individual particle beams are focused by the third multi-lens array and, in particular, imaged onto the intermediate image plane.

[0055] According to a further specific embodiment of the present invention, the final beam shaping system may include the following: A final porous plate having multiple openings is provided, which is configured such that individual particle beams are partially incident on the final porous plate and absorbed thereon, and partially pass through the openings in the final porous plate; A multi-lens plate having multiple openings is disposed downstream of the final multi-aperture plate in the beam path, such that the individual particle beams passing through the final multi-aperture plate also pass through the multi-lens plate; and At least one first aperture plate has a single opening and is disposed downstream of the multi-lens plate in the beam path, such that the individual particle beams passing through the multi-lens plate also pass through the opening in the at least first aperture plate; and The controller is further configured to supply an adjustable excitation to the at least one first aperture plate. Additionally, two, three, four, or more aperture plates may be provided, each of which can subsequently be supplied with adjustable excitation by the controller. Preferably, in this case, the particle beam system further includes a second multi-deflector array disposed in the beam path just upstream of the last multi-aperture plate, wherein the controller is further configured to supply individually adjustable excitation to the second multi-deflector array, thereby individually deflecting the individual particle beams.

[0056] With this specific embodiment variant, the pitch between the individual particle beams in the intermediate image plane can be affected. Specifically, the design of the global electrostatic electrode(s) downstream of the multilens plate allows for the generation of a negative image field curvature in the intermediate image plane. The amplitude of this negative image field curvature can be selected such that it fully compensates for the (positive) image field bending that subsequently occurs during the particle optical imaging from the intermediate image plane to the object plane. Therefore, in that case, no further image field curvature correction is required.

[0057] According to a further embodiment of the invention, the condenser lens system includes one or more global condenser lenses, particularly an electrostatic or magnetic dual condenser. However, the condenser lens system may also include a condenser lens array with multiple openings through which the individual particle beams pass. Therefore, the choice of the condenser lens system lies between a global lens system and a microlens system.

[0058] According to a further preferred embodiment of the invention, the object lens system includes a global magnetic object lens. In this case, all individual particle beams pass through the same (larger) opening of the magnetic object lens. However, the object lens system may also include an object lens array with multiple openings disposed in the beam path, such that the individual particle beams pass through these openings in the object lens array. In this case, the object lens array essentially represents an array of single lenses (Einzel-lens). Other embodiment variations are also possible. However, in any case, the object lens array (such as an example of a microlens array) is then manufactured using MEMS technology. The aforementioned field lens system has a focusing effect on these individual particle beams. This means that the individual particle beams form an intersection point in this direction of the object lens system. Preferably, this intersection point is located upstream of the object lens. If an objective lens array is used instead of a global magnetic objective lens, the intersection points of the individual particle beams required in the particle optical beam path can also be omitted. This is advantageous due to the Coulomb effect. In this case, the objective lens array is positioned just upstream of the intersection points of the individual particle beams; however, this has the consequence that the aperture pitch in the objective lens array is significantly smaller than the pitch of the individual particle beams in the intermediate image plane. Therefore, it is preferable that no intersection points of the individual particle beams are provided between the field lens system and the object plane. In particular, no intersection points are subsequently provided in that region of the objective lens system.

[0059] According to a further embodiment of the invention, the latter, as described above in several specific variants, relates to a multi-beam particle microscope with a particle beam system. In this case, the multi-beam particle microscope may, in a manner known per se, include a beam splitter to separate the primary particle beam from the secondary particle beam. Furthermore, it may, in a manner known per se, include a detection unit that facilitates the spatial resolution detection of one of the secondary electron beams.

[0060] The specific embodiments described above with respect to the first and second aspects of the present invention can be combined in whole or in part with each other, as long as there is no technical contradiction. Simple Explanation of the Diagram

[0061] The invention will be better understood with reference to the accompanying drawings. In these drawings:

[0062] Figure 1 shows a schematic example of a multibeam particle microscope;

[0063] Figure 2 shows a schematic illustration of a multi-source system according to the present invention;

[0064] Figure 3 shows a schematic example of a particle beam system that includes a multi-source system and further system components;

[0065] Figure 4 shows a schematic example of a particle beam system including a multi-source system, an object lens array, and further system components;

[0066] Figure 5 shows a particle beam system used to correct the direction of individual particle beams;

[0067] Figure 6 shows a magnetic field generation component above a multi-source particle according to a first paradigm;

[0068] Figure 7 shows a hierarchy of magnetic field generation components based on a second paradigm of multi-source particle generation; and

[0069] Figure 8 shows a magnetic field generating component above a multi-source particle according to a third paradigm. Implementation

[0070] Figure 1 is a schematic illustration of a particle beam system 1 in the form of a multi-beam particle microscope 1 (which uses multiple particle beams). The particle beam system 1 generates multiple particle beams that strike the object to be examined to produce interaction products (such as secondary electrons) that are emitted from the object and subsequently detected. The particle beam system 1 is of the scanning electron microscope (SEM) type, which uses a plurality of primary particle beams 3 that are incident on the surface of the object 7 at a plurality of locations 5 and generate a plurality of electron beam points or dots (which are spatially separated from each other). The object 7 to be examined can be of any desired type, such as a semiconductor wafer or a biological sample, and may contain one of miniaturized components or the like. The surface of the object 7 is disposed in the first plane 101 (object plane) of the objective lens 102 of the objective lens system 100.

[0071] The enlarged excerpt I1 in Figure 1 shows a plan view of the object plane 101 having a regular rectangular field 103 formed at incident positions 5 in the first plane 101. In Figure 1, the number of incident positions is 25, forming a 5 × 5 field 103. The number of incident positions, 25, is chosen for the sake of simplification. In practice, the number of beams, and therefore the number of incident positions, can be chosen to be significantly larger, such as 20 × 30, 100 × 100, and the like.

[0072] In the illustrated embodiment, the field 103 at incident position 5 is a substantially regular rectangular field with a constant pitch P1 between adjacent incident positions. Exemplary values ​​for this pitch P1 are 1 micrometer, 10 micrometers, and 40 micrometers. However, the field 103 may also have other symmetries, such as hexagonal symmetry.

[0073] The diameter of the beam points shaped in the first plane 101 can be relatively small. Exemplary values ​​for the aforementioned diameters are 1 nanometer, 5 nanometers, 10 nanometers, 100 nanometers, and 200 nanometers. The focusing of the particle beams 3 used to shape the beam points 5 is performed by the object lens system 100.

[0074] The primary particles impacting the object produce interaction products, such as secondary electrons, backscattered electrons, or primary particles that have undergone motion reversal for other reasons, which are emitted from the surface of the object 7 or from the first plane 101. These interaction products emitted from the surface of the object 7 are shaped by the object lens 102 to form secondary particle beams 9. The particle beam system 1 provides a particle beam path 11 for guiding these multiple secondary particle beams 9 to the detector system 200. The detector system 200 includes a particle optics unit with a projection lens 205 for guiding the secondary particle beams 9 to a particle multidetector 209.

[0075] The excerpt I2 in Figure 1 shows a plan view of plane 211 (in which the individual detection regions of the particle multi-detector 209 (on which the secondary particle beams 9 are incident at positions 213) are located). The incident positions 213 are located in a field 217 with regular pitches P2 relative to each other. Several exemplary values ​​of the pitches P2 are 10 micrometers, 100 micrometers, and 200 micrometers.

[0076] The primary particle beam 3 is generated in a beam generating device 300, which includes at least one particle source 301 (such as an electron source), at least one collimating lens 303, a multi-aperture arrangement 305, and a field lens 307, or a field lens system consisting of a plurality of field lenses. The particle source 301 generates at least one diverging particle beam 309, which is collimated or at least substantially collimated by the at least one collimating lens 303 to shape and irradiate the beam 311 of the multi-aperture arrangement 305.

[0077] The excerpt I3 in Figure 1 shows a plan view of the multi-aperture arrangement 305. The multi-aperture arrangement 305 includes a multi-aperture plate 313 having a plurality of openings or apertures 315 formed therein. The midpoints 317 of these openings 315 are positioned in a field 319, which is imaged onto a field 103 formed by the beam points 5 in the object plane 101. The pitch P3 between the midpoints 317 of the apertures 315 can have exemplary values ​​of 5 micrometers, 100 micrometers, and 200 micrometers. The diameters D of the apertures 315 are smaller than the pitch P3 between the midpoints of the apertures. Exemplary values ​​for the diameters D are 0.2 × P3, 0.4 × P3, and 0.8 × P3.

[0078] Particles from the irradiation beam 311 pass through the apertures 315 and form a particle beam 3. Particles from the irradiation beam 311 that strike the plate 313 are absorbed by the latter and do not contribute to the formation of the particle beam 3.

[0079] Due to the applied electrostatic field, the multi-aperture arrangement 305 focuses each of the particle beams 3, such that the beam focus 323 is formed in the plane 325. Alternatively, the beam focus 323 may be virtual. The diameter of the beam focus 323 may be, for example, 10 nanometers, 100 nanometers, and 1 micrometer.

[0080] Field lens 307 and object lens 102 provide a first imaging particle optical unit for imaging a plane 325 (in which the beam focal points 323 are formed) onto a first plane 101, such that the field 103 of the incident position 5 or beam point appears therein. If the surface of the object 7 is disposed in the first plane, the beam points are correspondingly formed on the surface of the object.

[0081] The object lens 102 and projection lens arrangement 205 provide a second imaging particle optics unit for imaging the first plane 101 onto the detection plane 211. Therefore, the object lens 102 is a lens that is part of both the first and the second particle optics unit, while the field lens 307 belongs only to the first particle optics unit, and the projection lens 205 belongs only to the second particle optics unit.

[0082] The beam switch 400 is disposed in the beam path of the first particle optical unit between the multi-aperture arrangement 305 and the object lens system 100. The beam switch 400 is also part of the second optical unit in the beam path between the object lens system 100 and the detector system 200.

[0083] Further information regarding the multi-beam particle system and components used therein (such as, for example, particle sources, multi-aperture plates, and lenses) is available from several international patent applications WO 2005 / 024881 A2, WO 2007 / 028595 A2, WO 2007 / 028596 A1, WO 2011 / 124352 A1, and WO 2007 / 060017 A2, as well as the German patent applications DE 10 2013 016 113 A1 and DE 10 2013 014 976 A1, the entire disclosure of which is incorporated herein by reference.

[0084] The plurality of particle beam systems further includes a computer system 10, which is also configured to control the individual particle optics components of the plurality of particle beam systems and to evaluate and analyze the signals obtained by the multiple detectors 209. In this case, the computer system 10 may be constructed from a plurality of individual computers or components. Furthermore, it may contain the controller according to the invention.

[0085] Figure 2 shows a schematic illustration of a multi-source system 500 according to the present invention. In this case, the multi-source system 500 includes a multi-source particle system, which is illustrated in this exemplary example by particle sources 501, 502, 503, and 504. The multi-source particle system is an array of electron emitters manufactured using MEMS technology. For example, the emitted charged particles are electrons generated by field emission. These form individual particle beams 3. Since the brightness of the individual particle sources 501, 502, 503, and 504 can deviate from each other, the individual particle beams 3 are pre-shaped in the multi-source system 500. Specifically, the beam current intensity of the individual particle beams 3 is set by means of the multi-source system 500. Further (rough or preliminary) beam shaping is also possible or schematically illustrated.

[0086] Specifically, the electrons leave the tips of the particle sources 501, 502, 503, and 504, the tips 511, 512, 513, and 514 being indicated by the tip of the "V".

[0087] After emission, the individual particle beams 3 pass through a first porous plate 521 (to which a voltage U1 has been applied in this exemplary example). In this case, the first porous plate 521 serves as an extraction electrode. Here, the openings in the first porous plate 521 are selected such that the first porous plate 521 blocks multiple portions of the emitted individual particle beams.

[0088] The first multi-lens array 523 is disposed downstream of the first multi-aperture plate 521 in the beam path. It has multiple individually adjustable particle lenses, shown in Figure 2 by flat cylinders. For example, these can be annular electrodes. In the illustrated example, a voltage U2 + Vi is applied to the first multi-lens array 523. In this case, the particle lenses of the first multi-lens array 523 can be controlled by a controller 10. The controller 10 is configured to supply individually adjustable excitation to the particle lenses, and thus individually adjust the focusing of the associated particle lens for each individual particle beam 3. The second multi-aperture plate 522 is disposed downstream of the first multi-lens array 523 in the beam path. In the illustrated example, a substantial voltage U1 is then applied to it. Therefore, the first multi-aperture plate 521, the first multi-lens array 523, and the second multi-aperture plate 522 form a series of single lenses for the individual particle beams 3. Overall, a focusing effect is exhibited for the individual particle beams.

[0089] The focusing effect on these individual particle beams varies depending on the voltage Vi selected. Different focusing or extensions result in different ranges. This is evident when considering the beam current limiting aperture plate 524 (which is disposed downstream of the second aperture plate 522 in the beam path). The openings in the beam current limiting aperture plate 524 are smaller in diameter than those in the second aperture plate 522 and the first multi-lens array 523. Generally, all plates or arrays are arranged such that their openings are concentrated above each other. According to an alternative embodiment of the invention, the second aperture plate 522 and the beam current limiting aperture plate 524 can also be functionally combined or aggregated.

[0090] In the illustrated example, the voltage V1 is selected such that the associated lens system is strongly excited or the individual particle beams 3 are strongly focused. In this process, it passes almost entirely through the beam current limiting aperture plate 524. In contrast, the second and fourth lens systems of the first multi-lens array 523 are less strongly excited, and the individual particle beams 3 passing through them extend over a larger area. Therefore, a larger proportion of these associated individual particle beams 3 are blocked by the beam current limiting aperture plate 524. The third lens system in the first multi-lens array 523 experiences the least strain, and the associated individual particle beams 3 extend to the maximum possible range. Therefore, in this case, a larger portion of the individual particle beams 3 are blocked at the beam current limiting aperture plate 524. The voltages at these lenses in the first multi-lens array 523 can now be selectively chosen such that the beam current intensity of these individual particle beams 3 is approximately the same after passing through the beam current limiting aperture plate 524. Thus, the different brightness levels of the particle sources 501, 502, 503, and 504 can be corrected or pre-corrected for subsequent particle optical imaging. Preferably, immediately after the beam current limiting aperture plate 524, the following relationship applies to the deviation δ of the individual beam currents from the arithmetic mean of the beam currents: δ ≤ 5%, preferably δ ≤ 2%, and most preferably δ ≤ 1%.

[0091] A multi-deflector array 525 is provided in the beam path below the beam current limiting aperture plate 524. This multi-deflector array can also be excited by the controller 10. Here, a voltage U2 can be applied selectively and individually to each aperture in the multi-deflector array 525. The direction of these individual particle beams 3 can be corrected based on the applied voltage and the direction of the electric field in the deflector. This is particularly important if the beam 3 is incident on the beam current limiting aperture plate 524 in a manner not exactly parallel to the optical axis Z (not illustrated here). This may be the case if the order of these plates is not perfectly aligned; in practice, the accuracy of aligning these plates relative to each other is limited, for example, resulting in tilted beam axes. The correction function of the deflectors in the multi-deflector array 525 is illustrated by way of example for the individual particle beam 3 originating from the rightmost part of the source 504: in this case, the individual particle beam 3 is significantly deflected to the left.

[0092] Furthermore, in the example shown, the multi-source system 500 includes a multi-aberration compensator array 526.

[0093] In the example shown, all components of the multi-source system 500 can be controlled by the controller 10. In this case, the controller 10 may be the same as the overall controller of the multibeam particle microscope 1. However, it may also be a separate controller 10.

[0094] Here, the dimensions of the multi-source system 500 are relatively small in the direction of the optical axis Z (not shown): in the example provided, the overall range in the direction of the optical axis Z can be less than 20 mm.

[0095] Figure 3 shows a schematic illustration of a particle beam system 1 comprising a multi-source system 500 and further system components. The beam paths are presented in a very simplified manner. Specifically, Figure 3 shows the integration of the multi-source system 500 according to the invention into an existing particle beam system 1. Multiple individual particle beams 3 are generated by the multi-source system 500, and these individual particle beams 3 are pre-shaped. In particular, the different brightness levels of the particle sources 501, 502, and 503 are compensated in this process. Condensing lens systems CL1..N are disposed in the beam path downstream of the multi-source system 500. In particular, this can be multiple condensing lens systems. However, it is also possible to replace these global condensing lenses CL1..N with a condensing lens array.

[0096] The final beamshaping system 600 is located downstream of the condenser lens system CL1..N in the beam path. The latter is shown only schematically and in a very simplified manner. It includes the final multi-aperture plate. However, it may still include further particle optics components, such as a third multi-lens array or an aberration compensator array. Importantly, the final beamshaping of the individual particle beams 3 for allowing high-quality imaging is performed by means of the final beamshaping system 600. In this case, the individual particle beams are truncated by the final multi-aperture plate, and only the concentrated individual particle beam components pass through the final multi-aperture plate. This allows for the elimination or compensation of aberrations (which occur in the multi-source system 500 during beamshaping or have not yet appeared in the further beam path) in the further beam path. After passing through the final beamshaping system 600, the individual particle beams 3 are focused into the intermediate image plane 325. Therefore, the illustration in Figure 3 is also highly simplified to clearly ensure the appropriate hierarchy. Then, by means of subsequent particle optical imaging, the individual particle beams 3 focused in the intermediate image plane 325 are imaged onto the object plane 101. For this purpose, it is initially focused by the field lens system FL1..N (by which the individual particle beams 3 are focused). The individual particle beams 3 first cross at the intersection 401, are then focused by the global object lens 102 (in this case, the global magnetic object lens 102), and are imaged onto the sample 7 in the object plane 101 at the incident position 5. Secondary electron beams 9 are emitted from these incident positions 5, and these are separated from the main beams 3 by means of the beam switch 400. For simplicity, the detection system 200 with particle multi-detector 209 is not shown in Figure 3.

[0097] In summary, Figure 3 shows the combination of the multi-source system 500 according to the invention with the final beam shaping system 600 having a global lens element.

[0098] Figure 4 shows a further schematic illustration of a particle beam system 1 including a multi-source system 500 and further system components. The beam paths are presented in a very simplified manner. In these illustrations, the same reference numerals indicate the same elements. The differences between Figures 3 and 4 will be discussed in more detail below. Unlike Figure 3, Figure 4 includes an object lens array 102a. The latter is schematically illustrated and can be implemented, for example, by a single lens array. Unlike Figure 3, particle beam system 1 does not have a crossover point 401. The object lens array 102a is positioned so high or so early in the beam path of the particles that it is positioned upstream of the (theoretical) crossover point 401. The omission of the crossover point 401 is preferable considering the suppression of the Coulomb effect. Therefore, overall, Figure 4 shows a combination of the multi-source system 500 and the final beam shaping system 600 according to the invention, both having global lens elements (condenser lens system CL1..N and field lens system FL1..N) and a further microlens system presented in the form of an object lens array 102a. Here, the object lens array 102a can have different configurations. For example, it can include a plurality of sequentially arranged multi-aperture plates, to which voltage is applied in a suitable manner and particularly by means of a controller 10. Furthermore, or as an alternative, the object lens array 102a can include a further multi-lens array. In this specific embodiment variant illustrated in Figure 4, instead of the beam switch 400 incorporated into the projection path (not illustrated in the latter two) of the detection unit, a detection unit with segmented detectors can also be provided in this region of the object lens array 102a.

[0099] Figure 5 shows a particle beam system 1 used to correct the direction of individual particle beams 3 in a schematic and very simplified manner. A multi-source system 500 with particle sources 501, 502, 503, and 504 is illustrated in conjunction with a final beam shaping system 600. The final beam shaping system 600 includes a final multilens plate 601 through which individual particle beams 3a, 3b, 3c, and 3d pass. A final multiaperture plate (not illustrated here) is disposed above the multilens plate 601. Furthermore, the final beam shaping system 600 includes aperture plates 620, 630, and 640, to which a global electric field may be applied. Thus, this electrostatic field can be shaped in a targeted manner within this region of the final beam shaping system 600. Alternatively, a magnetic field may also be used for this purpose.

[0100] Specifically, these electromagnetic fields also affect the lead-out field near the final multi-aperture plate: depending on the voltage applied to the electrodes 620, 630, and 640, the lens field in the multi-lens plate 601, and therefore the focusing effect on the individual beams, can have different intensities. In particular, a suitable voltage at the electrodes 620-640 makes it possible for the lens field to have a weaker focusing effect on the individual particle beams in the outer regions (3a, 3d) than in the inner regions (3b, 3c). Therefore, the possible curvature of the image field can be compensated, and the focal distribution in the image field has a relative profile. However, in this case, the field distribution at the electrodes 620-640 also acts on the intermediate image in a reduced-size manner; that is, the beam pitch between the beams in the intermediate image plane becomes smaller. A multi-deflector array 610 positioned between the multi-source system 500 and the final beam shaping system 600 facilitates the correction of the beam pitch of the individual particle beams 3a, 3b, 3c, and 3d in the intermediate image (not illustrated here). In the illustrated example, each of the individual particle beams 3a and 3b is deflected to the left, while the individual particle beams 3c and 3d are deflected to the right by appropriate control of the deflectors in the multi-deflector array 610. With this specific embodiment variant, the pitch between the individual particle beams 3 in the intermediate image plane may be affected. Specifically, a negative field curvature can be generated in the intermediate image plane. The amplitude of this negative field curvature can be selected such that it fully compensates for the (positive) field curvature that occurs subsequently during the particle optical imaging from the intermediate image plane to the object plane. Therefore, in that case, no further field curvature correction is required.

[0101] A magnetic field is generated in this region of the multi-source particle system, allowing generalized angular momentum to be imprinted onto the emitted particles or electrons in a targeted manner. This generalized angular momentum collectively contributes to the telecentric incidence of the individual particle beams in the object plane 101 after passing through the particle beam system. This may compensate for Larmor rotation caused by magnetic immersion in this region of the object lens. Figures 6 to 8 show several examples in this regard:

[0102] Figure 6a shows a magnetic field generating component 700 for generating a diverging magnetic field. For this purpose, multiple coil windings 702 are provided in the pole shoe 701, wherein a rotationally symmetrical embodiment is about the optical axis Z. The magnetic field B is oriented as indicated by reference numeral 703. Projected onto the emitter plane of the multi-source system 500, the magnetic field B has a component perpendicular to the optical axis Z. At a right angle to this radial direction, the emitted electrons experience a corresponding initial angular distribution. The initial velocity vector system projected onto the emitter plane is schematically illustrated in Figure 6b using multiple arrows.

[0103] Figure 7a shows the magnetic field generating components used to generate a homogeneous magnetic field. This magnetic field essentially has no component orthogonal to the initial direction of the emitted electrons. Therefore, the corresponding initial angle distribution is either point-like or not shown (see Figure 7b).

[0104] Figure 8a shows a further example of shaping the magnetic field to imprint a specific initial angle distribution in the magnetic field onto the emitted electrons. Two concentric pole pieces 701 and 701a are illustrated; each contains multiple coil windings 702 and 702a, respectively. The direction of these magnetic field lines is indicated by 703, which is oriented in the relative direction between the two pole pieces 701 and 701a. Therefore, for the emitted electrons, this also produces an initial angle distribution traveling in the relative direction (see Figure 8b).

[0105] Generally, providing a magnetic field that is imprinted in a certain way allows the initial angular distribution of electrons to be selectively influenced during the emission from these multiple sources, thereby ensuring the telecentric conditions in the particle beam system 1 immediately after incident on object 7. This is particularly helpful for the good detection of HAR structures.

[0106] 1: Multibeam particle microscope; particle beam system 3: Particle beam; beam 3a, 3b, 3c, 3d: Individual particle beams 5: Position; Beam Point 7: Objects; Samples 9: Secondary particle beam 10: Computer system; controller 11: Particle Beam Path 100: Objective lens system 101: First plane; object plane 102: Objective lens; Objective lens system 102a: Objective lens array; Objective lens system 103: Regular rectangular field; field 200: Detection System 205: Projection Lens 209: Particle Multi-Detector 211: Plane; Detection plane 213: Position; Incident position 217, 319: Field 300: Beam generating device 301: Particle Source 303: Collimating Lens 305: Multi-aperture setting 307: Field lens; Field lens system 309: Diverging Particle Beam 311: Beam; beam of irradiating particles 313:Multi-aperture plate 315: Opening or aperture 317: Midpoint 323: Beam Focus 325: Plane; Intermediate Image Plane 400: Beam switch 401: Intersection 500: Multi-source system; multi-source particle system 501: Particle source; Multiple particle sources 502: Particle source; Multiple particle sources 503: Particle source; Multiple particle sources 504: Particle source; Multiple particle sources 511: Tip; First tip 512: Tip; second tip 513: Tip; third tip 514: tip; fourth tip 520: Suppression electrode 521: First multi-aperture plate; extractor 522: Second porous plate; corresponding electrode 523: First Multi-Lens Array 524: Beam Current Limiting Multi-Aperture Plate 525: Multi-deflector array 526: Multi-Aberration Compensator Array 600: Final Beam Shaping System 601: Last multi-lens plate; multi-lens plate 602: :Third Multilens Array 610: First Multi-Deflector Array 620: Second Multi-Deflector Array 630, 640: Aperture plate; Electrode 650: Electric field lines 700: Magnetic field generating component 701: Extreme shoe; Extreme groove 701a: Concentric pole shoe; pole groove 702: Coil winding; coil 702a: Coil winding 703: Magnetic Field CL1..N: Condensing lens system; Global condensing lens D: Diameter FL1..N: Field Lens System I1, I2, I3, I4: Excerpt P1, P2, P3, P4: Pitch U1: First voltage U2: Average or reference value U2 +Vi: Individual adjustable voltage Vi, V1: Voltage Z: Optical axis

Claims

1. A particle beam system (1) comprising: a multi-source system (500) including a multi-source particle system (501, 502, 503, 504), particularly an electron emitter array configured to generate multiple charged individual particle beams (3) by field emission; a first aperture plate (521) having multiple first openings through which the individual particle beams (3) pass at least partially; and a first multi-lens array (523) including multiple individual adjustable particle lenses and disposed downstream of the first aperture plate (521) in the beam path such that the individual particle beams (3) passing through the first aperture plate (521) also pass through the first multi-lens array (523). A second aperture plate (522) having multiple second openings is disposed in the beam path downstream of the first multilens array (523) such that the individual particle beams (3) passing through the first multilens array (523) also pass through the second aperture plate (522); and a beam current limiting aperture plate (524) having multiple beam current limiting openings is disposed in the beam path downstream of the second aperture plate (522) such that the individual particle beams (3) are partially incident on and absorbed by the beam current limiting aperture plate (524) and partially pass through the openings in the beam current limiting aperture plate (524); and a controller (10) configured to supply an adjustable voltage to the particle lenses of the first multilens array (523) and thereby individually adjust the focusing of the associated particle lens for each individual particle beam (3).

2. The particle beam system (1) as claimed in claim 1 further comprises: a final beam shaping system (600) disposed downstream of the multi-source system (500) in the beam path, wherein the individual particle beams (3) thereunder have a final shape for subsequent optical imaging.

3. The particle beam system (1) as described in claim 1 or claim 2, wherein the first porous plate (521) is specifically implemented as an extraction electrode; and / or wherein the second porous plate (522) is specifically implemented as a corresponding electrode; and / or wherein the beam current limiting porous plate (524) is specifically implemented as an anode.

4. The particle beam system (1) as claimed in claim 1, wherein a first voltage (U1) is applied to the first aperture plate (521) and the second aperture plate (522); and wherein the individual adjustable voltages (U2+Vi) at the first multilens array (523) are different from the first voltage (U1).

5. The particle beam system (1) as claimed in claim 1, wherein a distance A is applied between the particle multi-source (501, 502, 503, 504) and the beam current limiting aperture plate (524) with the following: 0.1 mm ≤ A ≤ 30 mm.

6. The particle beam system (1) as claimed in claim 1, wherein immediately after passing through the beam current limiting aperture plate (524), the following relationship applies to the deviation δ of the individual beam currents from the arithmetic mean of the beam currents: δ ≤ 5%.

7. The particle beam system (1) as described in claim 1, wherein the multi-source system (500) further includes a suppression electrode (520).

8. The particle beam system (1) as claimed in claim 1, wherein the multi-source system (500) includes a second multi-lens array, wherein the second multi-lens array includes multiple individually adjustable and focusing particle lenses and is disposed in the beam path downstream of the beam current limiting aperture plate (524) such that the particles of the individual particle beams (3) passing through the beam current limiting aperture plate (524) also substantially pass through the second multi-lens array; and wherein the controller (10) is further configured to supply an adjustable voltage to the particle lenses of the second multi-lens array and thereby individually set the focusing of the associated particle lens for each individual particle beam.

9. The particle beam system (1) as claimed in claim 1, wherein the multi-source system (500) further includes a first multi-deflector array (610) through which the individual particle beams (3) pass and which is disposed in the beam path downstream of the beam current limiting aperture plate (524); and wherein the controller (10) is further configured to supply individual adjustable excitations to the first multi-deflector array (610) and thereby individually deflect the individual particle beams (3).

10. The particle beam system (1) as claimed in claim 1, wherein the multi-source system (500) further includes a multi-aberration compensator array through which the individual particle beams pass; and wherein the controller (10) is further configured to supply an adjustable excitation to the multi-aberration compensator array.

11. The particle beam system (1) as described in claim 1, wherein the multi-source system (500) is manufactured at least in part using microelectromechanical systems (MEMS) technology.

12. The particle beam system (1) as claimed in claim 1, wherein the particle multi-source (500) has at least one of the following emitter types: metal emitter, silicon-based emitter, carbon nanotube-based emitter.

13. The particle beam system (1) as claimed in claim 1 further includes a magnetic field generating member (700) configured such that the multiple particle sources (501, 502, 503, 504) are disposed in a magnetic field (703).

14. The particle beam system (1) as claimed in claim 13, wherein the magnetic field (703) generated by the magnetic field generating member (700) has a component perpendicular to and / or parallel to the emission direction of the charged particles from the multiple sources (501, 502, 503, 504).

15. The particle beam system (1) as claimed in claim 13, wherein the magnetic field generating member (700) is specifically implemented such that the initial angular distribution of one of the charged particles caused by the magnetic field (703) after the charged particles are emitted from the particle source (501, 502, 503, 504) is determined by the radial distance between the relative particle source (501, 502, 503, 504) and the optical axis of the particle beam system (1).

16. The particle beam system (1) as claimed in claim 2 further comprises: a condenser lens system (CL1..N) disposed downstream of the multi-source system (500) and upstream of the final beam shaping system (600) in the direction of the beam path; a field lens system (FL1..N) disposed downstream of the final beam shaping system (600) in the direction of the beam path; and an object lens system (102, 102a) disposed downstream of the field lens system (FL1..N) in the direction of the beam path, wherein an intermediate image plane (325) is formed between the final beam shaping system (600) and the field lens system (FL1..N).

17. The particle beam system (1) as claimed in claim 16, wherein the final beam shaping system (600) comprises: a final aperture plate having multiple openings, configured such that the individual particle beams (3) are partially incident on and absorbed thereon and partially pass through the openings in the final aperture plate; and a second multilens array comprising multiple adjustable particle lenses, and configured in the beam path downstream of the final aperture plate such that the individual particle beams (3) passing through the final aperture plate also substantially pass through the second multilens array.

18. The particle beam system (1) as claimed in claim 2, wherein the final beam shaping system (600) comprises: a final porous plate having multiple openings, configured such that the individual particle beams are partially incident on the final porous plate and absorbed thereon, and partially pass through the openings in the final porous plate. A multi-lens plate (601) having multiple openings is disposed in the beam path downstream of the last multi-aperture plate, such that the individual particle beams (3) passing through the last multi-aperture plate also pass through the multi-lens plate (601); and at least one first aperture plate (620, 630, 640) having a single opening and disposed in the beam path downstream of the multi-lens plate (601), such that the individual particle beams (3) passing through the multi-lens plate (601) also pass through the opening in the at least one first aperture plate (620, 630, 640); and wherein the controller is further configured to supply an adjustable excitation to the at least one first aperture plate (620, 630, 640).

19. The particle beam system (1) as claimed in claim 18 further comprises: a second multi-deflector array (620) disposed in the beam path just upstream of the last multi-aperture plate; and wherein the controller is further configured to supply individual adjustable excitations to the second multi-deflector array (620) and thereby individually deflect the individual particle beams (3).

20. The particle beam system (1) as described in claim 16, wherein the focusing lens system (CL1..N) includes one or more global focusing lenses, particularly an electrostatic or magnetic dual focusing lens.

21. The particle beam system (1) as described in claim 16, wherein the condenser lens system (CL1..N) includes a condenser lens array having multiple openings through which the individual particle beams (3) pass.

22. The particle beam system (1) as described in claim 16, wherein the object lens system (102) includes a global magnetic object lens (102).

23. The particle beam system (1) as claimed in claim 16, wherein the object lens system (102) includes an object lens array (102a) having multiple openings disposed in the beam path such that the individual particle beams (3) pass through the openings in the object lens array (102a).

24. The particle beam system (1) as described in claim 23, wherein no intersection point of the individual particle beams (3) is provided between the field lens system (FL1..N) and the object plane (101).

25. A multi-beam particle microscope (1) comprising a particle beam system (1) as described in any one of claims 1 to 24 above.

Images